From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754205AbeDMJsS (ORCPT ); Fri, 13 Apr 2018 05:48:18 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:36586 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753238AbeDMJsR (ORCPT ); Fri, 13 Apr 2018 05:48:17 -0400 X-Google-Smtp-Source: AIpwx4/BwHIBdUgH7NXZhXxbs7hk6jl9Bni1dOoO5LS0dRafhSkTXpIb+ECjOfPDR3J+mxloR91CXQ== To: x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, hpa@zytor.com From: Xiaoming Gao Subject: [PATCH] x86/tsc: fix 64bit divisor be truncated in calc_hpet_ref Message-ID: <38894564-4fc9-b8ec-353f-de702839e44e@gmail.com> Date: Fri, 13 Apr 2018 17:48:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="------------B00133F40DFE9772D6ACE9BC" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------B00133F40DFE9772D6ACE9BC Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit From ba3d2fb699c4d8ee61b05d7e70be48b9c4e22baf Mon Sep 17 00:00:00 2001 From: Xiaoming Gao Date: Fri, 13 Apr 2018 17:05:18 +0800 Subject: [PATCH] x86/tsc: fix 64bit divisor be truncated in calc_hpet_ref the HPET frequency got larger on intel skylake, thus could cause tmp to exceed 32bits. do_div will truncate 64bits tmp to 32bits, so the frequency calced via HPET will be wrong, use div64_u64 can fix it. Signed-off-by: Xiaoming Gao ---  arch/x86/kernel/tsc.c |    2 +-  1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 9714a7a..8700269 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -160,7 +160,7 @@ static unsigned long calc_hpet_ref(u64 deltatsc, u64 hpet1, u64 hpet2)      hpet2 -= hpet1;      tmp = ((u64)hpet2 * hpet_readl(HPET_PERIOD));      do_div(tmp, 1000000); -    do_div(deltatsc, tmp); +    deltatsc = div64_u64(deltatsc, tmp);      return (unsigned long) deltatsc;  } -- 1.7.1 --------------B00133F40DFE9772D6ACE9BC Content-Type: text/plain; charset=UTF-8; name="0001-x86-tsc-fix-64bit-divisor-be-truncated-in-calc_hpet_.patch" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename*0="0001-x86-tsc-fix-64bit-divisor-be-truncated-in-calc_hpet_.pa"; filename*1="tch" RnJvbSBiYTNkMmZiNjk5YzRkOGVlNjFiMDVkN2U3MGJlNDhiOWM0ZTIyYmFmIE1vbiBTZXAg MTcgMDA6MDA6MDAgMjAwMQpGcm9tOiBYaWFvbWluZyBHYW8gPG5ld3Rvbmdhb0B0ZW5jZW50 LmNvbT4KRGF0ZTogRnJpLCAxMyBBcHIgMjAxOCAxNzowNToxOCArMDgwMApTdWJqZWN0OiBb UEFUQ0hdIHg4Ni90c2M6IGZpeCA2NGJpdCBkaXZpc29yIGJlIHRydW5jYXRlZCBpbiBjYWxj X2hwZXRfcmVmCgp0aGUgSFBFVCBmcmVxdWVuY3kgZ290IGxhcmdlciBvbiBpbnRlbCBza3ls YWtlLCB0aHVzIGNvdWxkIGNhdXNlIHRtcCB0bwpleGNlZWQgMzJiaXRzLgpkb19kaXYgd2ls bCB0cnVuY2F0ZSA2NGJpdHMgdG1wIHRvIDMyYml0cywgc28gdGhlIGZyZXF1ZW5jeSBjYWxj ZWQgdmlhCkhQRVQgd2lsbCBiZSB3cm9uZywgdXNlIGRpdjY0X3U2NCBjYW4gZml4IGl0LgoK U2lnbmVkLW9mZi1ieTogWGlhb21pbmcgR2FvIDxuZXd0b25nYW9AdGVuY2VudC5jb20+Ci0t LQogYXJjaC94ODYva2VybmVsL3RzYy5jIHwgICAgMiArLQogMSBmaWxlcyBjaGFuZ2VkLCAx IGluc2VydGlvbnMoKyksIDEgZGVsZXRpb25zKC0pCgpkaWZmIC0tZ2l0IGEvYXJjaC94ODYv a2VybmVsL3RzYy5jIGIvYXJjaC94ODYva2VybmVsL3RzYy5jCmluZGV4IDk3MTRhN2EuLjg3 MDAyNjkgMTAwNjQ0Ci0tLSBhL2FyY2gveDg2L2tlcm5lbC90c2MuYworKysgYi9hcmNoL3g4 Ni9rZXJuZWwvdHNjLmMKQEAgLTE2MCw3ICsxNjAsNyBAQCBzdGF0aWMgdW5zaWduZWQgbG9u ZyBjYWxjX2hwZXRfcmVmKHU2NCBkZWx0YXRzYywgdTY0IGhwZXQxLCB1NjQgaHBldDIpCiAJ aHBldDIgLT0gaHBldDE7CiAJdG1wID0gKCh1NjQpaHBldDIgKiBocGV0X3JlYWRsKEhQRVRf UEVSSU9EKSk7CiAJZG9fZGl2KHRtcCwgMTAwMDAwMCk7Ci0JZG9fZGl2KGRlbHRhdHNjLCB0 bXApOworCWRlbHRhdHNjID0gZGl2NjRfdTY0KGRlbHRhdHNjLCB0bXApOwogCiAJcmV0dXJu ICh1bnNpZ25lZCBsb25nKSBkZWx0YXRzYzsKIH0KLS0gCjEuNy4xCgo= --------------B00133F40DFE9772D6ACE9BC--